An uninterruptible power supply, well known as a UPS, is typically used as a buffer between commercially supplied power and an electrical load. A UPS typically monitors the supplied power and will transfer to a backup mode if it detects a power failure or an abnormal voltage or current. During the transfer between the main power supply and the backup mode, energy is typically provided by a DC Bus comprising a capacitor. The amount of capacitance needed depends, in part, on how quickly the power failure or abnormal voltage is detected. Higher capacitance capacitors tend to be more expensive and take up more space in the UPS.